Why can't this be fixed? Your ship is in my game, and your game is sending my game updates telling me where your ship is, how it's moving, where it's firing, how much health it has, and so on. When we're done, both our games are going to update the central server, which is always there, with who won and who lost.
It's sending the data, as you say, to YOUR machine. Not a central server. I'm not a techie but I can't help but think there's all sorts of issues involved in monitoring what goes on on individual machines. I don't need to be a techie to remember the various 'spyware' storms that have blown up when game companies have taken it upon themselves to install stuff on people's machines. And you would need something on each machine to send the data needed to pass judgement on a disconnect.
Change the incentives and the behaviour will change. Try and penalise people based on trends or try to install anything remotely resembling spyware on a player's machine and you're in a world of PR hurt.